Compressor



Dec. 3, 1968 5 v, MCMULLIN ET AL 3,414,187

COMPRESSOR Filed Sept. 14, 1966 United States Patent 3,414,187 COMPRESSOR Edward V. McMullin, St. Louis, and James M. Edwards, Florissant, M0., assignors to Laclede Gas Company, a corporation of Missouri Filed Sept. 14, 1966, Ser. No. 579,262 5 Claims. (Cl. 23056) ABSTRACT OF THE DISCLOSURE A refrigerant compressor utilizing a two cycle gas fired engine having a firing piston connected to a compressor piston with a guide piston connected to the compressor piston and to a flywheel to provide a source of standby stored energy to the firing piston in the event the operation of the compression piston is upset by sudden load changes.

This invention relates to a compressor and particularly to a compressor operated by a two cycle engine.

One of the principal objects of the present invention is to provide a compressor system utilizing a two cycle engine which is adaptable to be driven by natural or artificial gas and which is utilized to drive a compressor piston for an air conditioner. Heretofore gas fired air conditioners have been known, but the expense of their initial cost has limited their use. The present invention utilizes an inexpensive lawn mower type two cycle engine to drive the compression cylinder.

Another object of the present invention is to provide a compressor in which a two cycle engine operates a refrigerant compression piston with a crankshaft and flywheel arrangement connected to the piston to compensate for load changes on the system. While it is conventional to use a piston engine to drive a compressor, the energy from the piston is transferred to the compressor through a crankshaft and flywheel. This arrangement is inetficient and not adaptable to sustained high speed operations and therefore involves high initial cost. Typical machines of this type are in US. Patent Nos. 2,610,785 and 1,638,418.

Also, it has been proposed to use a free piston engine to directly drive a compressor piston. This arrangement can utilize the high speeds to reduce first cost but must be supplemented with complicated load control equipment which presently causes the cost of the entire unit to be excessive. Typical devices of this type are shown in US. Patent Nos. 3,216,651 and 3,229,900.

The present invention utilizes a construction wherein the energy from the firing piston is directly and efliciently transferred to a compressor piston and the compressor piston is connected to a crankshaft and flywheel to provide a source of stored energy to compensate for load changes in the system and, depending on the refrigerant used, to provide energy for all or a part of the energy for the return stroke of the firing piston. This combination of parts provides for a low initial cost and extended life of the unit since the moving parts convey only a small portion of the utilized horsepower.

These and other objects and advantages of the present invention will become apparent hereinafter.

The present invention comprises a compressor having a drive piston connected to a refrigerant compressor piston with a flywheel and crankshaft arrangement connected to the system to pro-vide a source of stored energy for the engine piston. The present invention further comprises the apparatus and system hereinafter described and claimed.

In the drawings, wherein like numbers refer to like parts wherever they occur, the figure is a vertical sec- Patented Dec. 3, 1968 tional view taken through a preferred embodiment of the present invention.

The figure shows an engine 10 of the two cycle type, comprising a cylinder 11 having a spark plug 12 in the cylinder 11. A piston 13 is reciprocally mounted in the cylinder 11 and comprises a firing chamber 14 ahead of the piston 13 and a compression chamber 15 behind the piston 13. A carburetor 16, having a reed plate 17 or check valve arrangement mounted therein, is connected to a passage 18, which communicates with the firing chamber 14 when the piston 13 is at the downwardmost portion of its stroke. An exhaust port 19 communicates with a mufller 20 whereby the burned exhaust gasses are exhausted from the firing chamber 14 when the piston 13 approaches the end of its power stroke.

A passage 21 communicates the compression cylinder 15 with the intake passage 18 so that as the fuel and air mixture are drawn into the compression chamber 15, they are partially compressed during the downward stroke of the piston 13 and when the piston 13 uncovers the exhaust port 19 and the intake port 18, the mixture is forced into the firing chamber 14. When the piston 13 starts its upward stroke, the mixture is compressed in the firing chamber 14 and, when compressed, is ignited by the spark 12. This is a conventional firing cycle for a two cycle engine.

Mounted beneath and adjacent to the engine cylinder 11 is a compression cylinder 22 which has a compression piston 23 reciprocally mounted therein. A rod 24 connects the compression piston 23 to the engine or firing piston 13 and is guided by means of an opening 25 through a wall 11a of the cylinder 11. A seal means 26 in the opening 25 prevents passage of compressed fuel and air from the chamber 15.

The compression cylinder 22 comprises a compression chamber 27 ahead of the piston 23 and an air space chamber 28 behind the piston 23. The compression chamber 27 is provided with an intake port 29 and outlet port 30, into which are threaded check valves or reed plugs 31 and 31a. The ports 29 and 30 also are connected to fluid conduits 32 for communicating refrigerant to and from the compression chamber 27. In operation, as the compression piston 23 moves upwardly, refrigerant is sucked past the inlet valve 31 into the compression chamber 27. As the piston 23 moves downwardly, the fluid is compressed in the compression chamber 27 and passed outwardly through the outlet valve 31a. When the engine firing chamber 14 is exhausted through the outlet port 19, the compressed fiuid remaining in the compression chamber 27 drives the compression piston 23 and the firing piston 13 upwardly, so that the compression piston 23 acts as a free piston even though it is connected to the piston 13 by the rod 24. 1

Connected to the compression cylinder 22 is a guide piston cylinder 33, through which a guide piston 34 is reciprocally movable. A connecting rod 35 connects the compression piston 23 to the guide piston 34. Passages 36 communicate the front and back faces of the guide piston 34 for passage of air therethrough to prevent fluid being pressurized in the space between the front face 37 of the guide piston and the bottom wall 38 of the compression cylinder 22. A seal 39 around the rod 35 where it passes through the Wall 38 prevents compressed refrigerant from passing into the said space from the compression chamber 27.

A crankshaft 40 is rotatably mounted in a crankcase 41 by means of bearings 42, and is connected by a con necting rod 43 to the guide piston 34. A flywheel 44 is connected to one end of the crankshaft 40 and the other end of the crankshaft may be connected to a fan or other light work. A magneto 45 connected to the spark plug 12 provides timing and ignition for the engine 10.

The flywheel 44 is rotated by the crankshaft 40 through the connecting rod 43 and the pistons 13, 23 and 34 and the rods 24 and 35 therebetween. However, contrary to the usual operation of a crankshaft and flywheel, all or a portion of the return energy for the firing piston 13 can be provided by the compressed refrigerant in the chamber 27 rather than all of this energy being provided the inertia of the flywheel 44. The flywheel 44 also provides a source of standby stored energy for returning the firing piston 13 to its firing position in the event that the operation of the refrigerant is upset by sudden load changes on the system. The flywheel 44 acts to keep the firing piston 13 running in a smooth steady operation so as to avoid interrupting its cycle and causing the engine to stop.

In operation, the firing piston 13 is used to compress a mixture of fuel and air in the firing chamber 14, where it is ignited by the spark plug 12. This explosition forces the firing piston 13 downwardly until the exhaust is passed through the port 19. In the meantime on the upward stroke of the piston 13, a mixture of air and fuel has been sucked into the compression chamber 15. This mixture is compressed on the downward stroke of the piston 13, and when the exhaust port 19 and the intake port 18 are opened, the compressed mixture is passed to the firing chamber 14. Thereafter, the foregoing cycle is repeated.

On the upward stroke of the firing piston 13, the compression piston 23 also is moved upwardly and refrigerant flows into the compression chamber 27. When the firing piston 13 is moved downwardly, the refrigerant in the compression chamber 27 is compressed and forced out through the outlet valve 31a. When the gasses are exhausted from the firing chamber 14, the compressed fluid remaining in the compression chamber 27 forces the compression piston 23 and the firing piston 13 upwardly for another cycle. At the same time, the crankshaft 40 and the flywheel 44 are rotated. This continues the operation of the magneto 45 and whatever work may be connected to the other end of the crankshaft 40. In the event that some outside force interrupts the operation of refrigerant in the compression chamber 27, the flywheel 44 has sufficient energy to return the firing piston 13 to its upward position to avoid interrupting operation of the engine 10.

Thus, it is seen that the present invention achieves all of the objects and advantages sought therefor.

This invention is intended to cover all changes and modifications of the examples of the invention herein chosen for purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. A refrigerant compressor comprising (a) a two cycle engine including an engine cylinder having a firing piston reciprocally mounted therein, the engine cylinder having a firing chamber and a fuel-air compressing and scavenging chamber on opposite sides of said piston,

(b) a refrigerant compressor cylinder having a refrigerant compression piston reciprocally mounted therein, the refrigerant compressor cylinder having a refrigerant chamber separated from the firing chamber of the engine cylinder by the fuel-air compressing and scavenging chamber,

(c) means rigidly connecting the firing piston and refrigerant compression piston whereby the two move in unison to transmit energy of one directly to the other,

(d) fluid inlet and outlet means in the refrigerant compressor chamber behind the compression piston, and

(e) a flywheel connected to one of the pistons to provide a source of stored energy for returning the firing piston to its firing position and prevent interruption of the firing cycle in the event of load change on the compressed refrigerant fluid.

2. The structure of claim 1 wherein the fluid inlet and outlet means in the compressor cylinder comprise threaded ports in the cylinder and externally threaded reed plate check valves mounted in the threaded ports with threaded conduit connectors also mounted in the ports.

3. The structure of claim 1 including a guide cylinder mounted between the compressor cylinder and the crankshaft, a guide piston of substantially the same diameter as the firing piston and the refrigerant compressor piston in the guide cylinder, and means connecting the guide piston to the compression piston and means connecting the guide piston to the crankshaft.

4. A compressor comprising (a) a two cycle gas fired engine including a cylinder having a piston reciprocally mounted therein,

(b) a compressor cylinder positioned adjacent to the engine and having a compression piston reciprocally mounted therein, the compressor cylinder having a compression chamber defined between a Wall thereof and a face of the compression piston,

(c) means connecting the engine piston and compression piston whereby the two move in unison to contract the size of the compression chamber in the compressor cylinder on the firing stroke of the engine piston,

(d) refrigerant fluid inlet and outlet ports in the compression chamber of the compressor cylinder,

(e) refrigerant conduits communicating with the inlet and outlet ports,

(f) inlet and outlet valve means for establishing and interrupting refrigerant flow to and from the compression chamber to provide a source of pressurized refrigerant from the outlet port on the firing stroke of the engine piston and also to provide a source of energy for returning the firing piston to its firing position,

(g) a guide cylinder mounted adjacent to the compressor cylinder,

(h) a guide piston reciprocally mounted in the guide cylinder,

(i) means connecting the guide piston to the compression piston to move the two in unison,

(j) a crankshaft connected to the compressor piston,

and

(k) a flywheel connected to the crankshaft and rotatable therewith to provide an auxiliary source of energy for returning the firing piston to its firing position in the event of interruption or load change on the refrigerant fluid.

5. The structure of claim 4 wherein the fluid inlet and outlet means in the compressor cylinder comprise threaded ports in the cylinder and externally threaded reed plate check valves mounted in the threaded ports with threaded conduit connectors also mounted in the ports.

References Cited UNITED STATES PATENTS 832,592 10/1906 Bush 230-56 984,320 2/1911 Thompson et al. 103-153 1,508,568 9/1924 Nelson 230229 2,674,401 4/1954 Mallory 23056 2,878,990 3/1959 Zurcher 230-172 ROBERT M. WALKER, Primary Examiner. 

